This invention relates to a spinal midline indicator.
It is important for a surgeon performing an ALIF (anterior lumbar interbody fusion) or ACIF (anterior cervical interbody fusion) cage or spinal disc replacement procedure to be able accurately to establish the centre- or midline of the spine. It is only once the surgeon has correctly established the position of the spinal midline that he is able to place the cage or spinal disc accurately on that midline. ff-centre placement will result in eccentric loading and possible early failure or accelerated wear.
At present, surgeons attempt to establish the spinal midline by visual inspection of an A-P (anterior-posterior) image. However this is often inaccurate, and can lead to subsequent off-centre placement of the cage or disc with potential disadvantages as described above.
The present invention seeks to provide an instrument which will facilitate accurate establishment of the spinal midline.